Lawn-mowers are known which do not have any system for detecting a grass surface or an external obstacle close thereto, such as a wall, a fencing, a table, etc.
The above mentioned lawn-mowers exhibit some drawbacks. A first drawback lies in the fact that the known lawn-mowers cannot establish, during their operation, whether they actually cut the grass or run idle.
More specifically, the known lawn-mowers cannot establish, for example, whether they are on a grass surface or on a floor or on any surface with no grass to be cut.
A further drawback is given by the fact the known lawn-mowers are unable to identify possible obstacles along the direction of advancement during their operation, thereby causing unavoidable dangerous conditions for people close to the apparatus.